He was the son of Gisela, a widowed refugee from East Prussia, mother of three, and of Stanislaw Wisniewski from Kutno, a former forced labourer in German Arbeitseinsatz during World War II, who died on 9 October 1953 in Tübingen.
[1] During his youth, Wisniewski's mother warned him not to mention his father's past, since a number of former SS and SA members lived in the village.
At the time, other future members of the RAF, Ulrike Meinhof (Bambule) and Gudrun Ensslin, protested also against such institutions.
After the death of Holger Meins, a member of the RAF, as the result of a hunger strike in 1974, Wisniewski joined the group.
[4] In the summer of 1976, Wisniewski was in a training camp of the Popular Front for the Liberation of Palestine (PFLP) in Southern Yemen.
[2] In August 1977, he participated in a bank robbery in Essen, to finance the upcoming kidnapping of Hanns Martin Schleyer, an employers' representative and former SS member.
Weeks later, Schleyer was shot and killed in a forest[2][3] after the first generation RAF members died in Stammheim Prison.
On December 4, 1981, Stefan Wisniewski was convicted and sentenced to life in prison for murder, kidnapping, coercion of a constitutional body, and membership in a terrorist organization.